Is it possible to use the SC300 4.27 diff with the Supra Torsen LSD on my 95 SC400? Already have the Supra Torsen installed into my stock unit. It had 10 bolts I think.

Any thoughts on what the change might be on the dragstrip and for daily driving?

Thanks,

KC

 

To answer part of my own question I dug up Blizzy's old thread (whatever happened to him anyway?)?

The Torsen can be put into the 4.27 diff I'm just not 100% sure that the 300 diff bolts to the 400 driveshaft. Not sure if he changed anything on the diff end of the driveshaft since he did a 5-speed swap as well.

Thanks,

KC

 

I am pretty sure the propeller shaft will bolt on as is. However, if it does not, you can always swap over the companion flange, similar to what is done when swapping in a Supra Auto TT LSD pumpkin. You'll need a 25mm deep socket to do this.

 

Cool. I was thinking it was the same. If not, swapping the flange is easy enough.

If I'm thinking about it right, the 4.27 gear in place of the stock 3.92 would get me the 11's 1/4 mile I want so much. Right now, I trap at 115 or so at about 6000rpm. The 4.27 would put me at about redline when going through the traps and in theory, get me there a little faster.

KC

 

or the 4.27 will help you spin your tires faster in 1st and lose traction...

 

Maybe but not likely on the Mickey Thompson ET streets I use. I've cut a 1.68 on them and I'm pretty sure I'm barely working them. Small burn out and pressure set to 30psi. Haven't lost traction once with them. Worse case more burnout and lower pressure.

KC

 

so that means i should keep my stock differentials but just get an lsd?? btw how did it go at mooresville dragway?

 

it would depend on your build... but from what I read longer gears on turbo applications means more load on the engine keeping up your boost. Once again over kill on the gears will slow you down too.

 

Ya, depends on your setup. Are you sure you don't have a 4.08?

I didn't make it out to Mooresville. Went to Rockingham on Sunday, didn't run too great.

There is a science too it, which I am far from understanding. LOL. Right now, running the 1/4 mile, I'm at about 6000-6100 rpm going through the trap. The 4.27 should put me right at red-line through the trap. Since my peak hp is at redline, this should be a benefit. It will very likely slow me down a little as far as trap speeds but it should more than make up for it on the 1st half of the track.

And, if I'm not happy with it, I'll just swap it back and be out the cost of the diff.

KC

 

to be honest i don't even know. lol

 

Factory 5-speed = 4.08
Factory auto = 4.27

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I have a SC300 auto diff on the way. Since the 300 and 400 auto trannies are basically the same and have the same gearing, an SC400 with a 4.27 diff will have the same overall gear ratios as an auto SC300 does from the factory.

I wonder if using an SC300 speed sensor will make the speedo read correctly?

KC